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- Introduction
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1. Prions and amyloids: introduction
- Prof. Reed Wickner
- Mammalian Prions
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2. Transgenic mouse models of prion diseases
- Prof. Glenn Telling
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3. Mechanism of prion generation in vitro
- Dr. Surachai Supattapone
- Non-Prion Amyloids
- Yeast Prions
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6. Chaperones and prions
- Prof. Yury Chernoff
- Beneficial Amyloids
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7. The dark side of amyloid: PMEL, a natural amyloid in melanosome biogenesis
- Prof. Michael Marks
- Archived Lectures *These may not cover the latest advances in the field
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8. Predicting TSE transmission
- Prof. Jean Manson
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10. Yeast and fungal prions: a help or a hindrance?
- Prof. Reed Wickner
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11. [PIN+]: prions beget prions
- Prof. Susan Liebman
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12. Yeast prions and protein chaperones
- Dr. Daniel Masison
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13. Mechanisms of yeast prion propagation
- Prof. Mick Tuite
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14. Propagation and variability of the yeast [PSI+] prion
- Prof. Michael Ter-Avanesyan
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15. The genetics and biology of the [Het-s] prion of Podospora
- Prof. Sven Saupe
Printable Handouts
Navigable Slide Index
- Introduction
- Prion paradigm in yeast
- Hsp104 chaperone required for prions propagation
- Amyloid-like prion proteins in yeast
- [psi -] vs. [PSI +] cells
- Some genetic criteria suggestive of prions (1)
- Some genetic criteria suggestive of prions (2)
- Sup35 protein structure
- Different variants of [PSI +]
- Dominant prios compete better for soluble protein
- Variant differences are prion specific
- [PIN +] causes [PSI +] induction
- Excess Sup35 inhibit growth of [PIN +] cells
- [PIN +] phenotypes
- Genetics of [PIN +] (1)
- [PIN +] maintenance is independent of [PSI +] PD
- [PSI +] and [PIN +] can be lost independently
- Prions do not protect each other from being cured
- Genetics of [PIN +] (2)
- Reversible curing of [PIN +]
- Genetics of [PIN +] (3)
- Different variants of [PIN +]
- [PIN +] "Variants" are transferred by cytoduction
- [PSI +] phenotypes are not affected by [PIN +]
- [PIN +] effect on SDS resistant [PSI +] oligomers
- Some [PIN +] variants destabilize weak [PSI +]
- [PIN +] enhances the appearance of [URE3]
- [PIN +] enhances aggregation of polyQ
- Extensions affect [PIN +] dependence
- Candidate approach to identify the [PIN +] gene
- RNQ1 is required for [PIN +] propagation
- Rnq1 sedimentation in different [PIN +]'s
- Rnq1
- RNQ1-PD amyloid aggregates transmit [PIN+]
- [PIN +] and [PSI +] oligomers are distinct
- Pin+ is not caused by loss of Rnq1 function
- Models for [PSI +] appearance induction
- RNQ1 aggregates stimulate NM fiber formation
- NM fibers stimulate RNQ1-PD aggregate formation
- Can other prions cross-seed [PSI +] formation?
- Eleven QN-rich potential prions cloned
- Other prions enhance de novo [PSI +] appearance
- URE3 enhances Rnq1:GFP aggregate appearance
- Genes enhance Rnq1:GFP aggregate appearance
- Q103:GFP aggregates enhance PSI+ appearance
- Conclusions
- Acknowledgements
- Collaborators
- References
Topics Covered
- Prions are infectious proteins
- [PIN+] is a prion of Rnq1
- [PIN+] exists as different variants
- Prions can affect the stability of other variants of the same prion, or of heterologous prions
Talk Citation
Liebman, S. (2020, May 1). [PIN+]: prions beget prions [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved October 13, 2024, from https://doi.org/10.69645/OIPW1902.Export Citation (RIS)
Publication History
Financial Disclosures
- Prof. Susan Liebman has not informed HSTalks of any commercial/financial relationship that it is appropriate to disclose.
A selection of talks on Cell Biology
Transcript
Please wait while the transcript is being prepared...
0:00
In this seminar, I will tell you how the
presence of one yeast prion can enhance
the appearance of other yeast prions.
0:09
According to the prion
paradigm in yeast cells can
propagate prion proteins in either
the normal form or the prion form.
When propagated in the prion form,
they have a different phenotype than in
cultures where the protein is
propagated and the normal form.
Cells with the prion in the normal
form can be converted into
prion cultures by being
infected with prion seed.
Evidence suggests that
the prion seed is a fiber and
that the normal molecules
join this fiber at the ends.
0:46
The growth of the prion fiber is limited
by the fact that it only has two ends.
And as you could imagine, its ability to
segregate into budding daughter cells is
also limited by the number of prion
seeds that are present in the mother.
The Hsp104 chaperone whose
activity is known to disaggregate
aggregated proteins provides
the important activity for
the prion of cutting these fibers into
pieces, which provides additional ends and
additional seeds that can then
segregate into the daughters.
In the absence of Hsp104 of course,
the prions are not cut and they fail
to segregate and are lost, leading
to the curing of cells of the prion.
This also explains how the low
levels of guanidine hydrochloride,
known for many years to cure cells
of prions works and it does so
we now know by inhibiting
the activity of the Hsp104 chaperone.